Method of fuel injection rate control

Abstract

A method is disclosed for varying the rate of injection of fuel during a single injection of fuel into a cylinder of an internal combustion engine. The method includes the steps of supplying pressurized fuel to the fuel inlet of an electrically controlled fuel injector and switching the fuel injector alternately on and off at a predetermined rate to thereby control the average rate of discharge of fuel from the fuel injector. The fuel injector can be a solenoid operated injector in which case the rate of discharge of fuel from the fuel injector can be controlled by modulating the width and frequency of pulses used to switch the fuel injector on and off.

What is claimed is: 
     
       1. A method for controlling the rate of injection of fuel from an electrically operated fuel injector switchable between an on position to provide a first condition of fuel injection operation and to an off position to provide a second condition of fuel injection operation and controlled by an electronic control unit for pulsing fuel into the combustion chamber of an internal combustion engine operable over a wide range of speeds and loads, comprising the steps of: supplying pressurized fuel to the fuel inlet of said fuel injector; and   switching said fuel injector alternately between the on and off positions at a predetermined rate by electric signals from said electronic control unit to thereby control the average rate of discharge of fuel from said fuel injector into said combustion chamber to optimize fuel combustion therein.   
     
     
       2. The method of claim 1, wherein said fuel injector is a solenoid operated injector responsive to the electrical signals and wherein said switching step further comprises: operating said fuel injector with electrical pulses having a predetermined width and frequency.   
     
     
       3. The method of claim 2, wherein the frequency of said pulses is high enough to provide a continuous flow of fuel from said fuel injector. 
     
     
       4. The method of claim 2, further comprising the step of varying the width and frequency of said pulses. 
     
     
       5. The method of claim 4, further comprising the step of varying the width and frequency of said pulses over the course of a single injection.